CN106154759A - The lithographic equipment of a kind of recoverable material fluctuating and method - Google Patents

Abstract

The present invention discloses the lithographic equipment that a kind of recoverable material rises and falls, it is characterised in that including: illuminator, for providing a lithographic beam；Mask platform, is used for carrying mask；The vertical sensor of mask platform, for detecting and control the vertical position of a mask platform；Mask focusing and leveling system, for measuring the face shape of mask；Work stage, moves for bearing substrate, compensates mask and the low order amount of real estate shape；Substrate focusing and leveling system, for measuring the face shape of substrate；The vertical sensor of work stage, for detecting and control the vertical position of a work stage；Objective lens array, the two row object lens being made up of multiple single object lens, single object lens include upper movable eyeglass and lower moveable eyeglass, described upper movable eyeglass and lower moveable eyeglass have vertical adjustment function, upper movable eyeglass is used for compensating mask partial face shape high-order amount, and lower moveable eyeglass is used for compensating substrate partial face shape high-order amount；Mask focusing and leveling system and substrate focusing and leveling system are between two row object lens, and mask focusing and leveling system is positioned at the surface of substrate focusing and leveling system.

Description

The lithographic equipment of a kind of recoverable material fluctuating and method

Technical field

The present invention relates to a kind of integrated circuit equipment manufacturing field, particularly relate to lithographic equipment and method that a kind of recoverable material rises and falls.

Background technology

Material rises and falls, and the face shape caused because of gravity deformation including mask aligner mask version and substrate surface are uneven the face shape caused.Wherein, real estate shape can be divided into integral face shape and partial face shape.What integral face shape described is upper surface of base plate overall variation trend, correspond to the low order amount in real estate shape；What partial face shape described is in exposure field subrange, and the irregular height of upper surface of base plate rises and falls, and correspond to the high-order amount in real estate shape.

Mask gravity deformation can cause curvature of the image, causes image planes to deviate nominal position.Real estate shape can cause exposure field upper surface misaligned with exposure focal plane, and out of focus occurs.Actual exposure effect all can be had a negative impact by two kinds of face shapes.In NIKON's patent CN1379286A, CN101375372A, CN102346378A, by adjusting the curvature of the image that each camera lens of objective lens array vertical altimetric compensation mask gravity deformation causes.Said method main purpose is for correction mask version gravity deformation, does not consider mask gravity deformation and the impact on exposure effect of the large-size substrate face shape.

Summary of the invention

In order to overcome defect present in prior art, the present invention provides the lithographic equipment and method that a kind of recoverable material rises and falls.

In order to realize foregoing invention purpose, the present invention discloses the lithographic equipment that a kind of recoverable material rises and falls, it is characterised in that including: illuminator, for providing a lithographic beam；Mask platform, is used for carrying mask；The vertical sensor of mask platform, for detecting and control the vertical position of a mask platform；Mask focusing and leveling system, for measuring the face shape of mask；Work stage, moves for bearing substrate, compensates mask and the low order amount of real estate shape；Substrate focusing and leveling system, for measuring the face shape of substrate；The vertical sensor of work stage, for detecting and control the vertical position of a work stage；Objective lens array, the two row object lens being made up of multiple single object lens, single object lens include upper movable eyeglass and lower moveable eyeglass, described upper movable eyeglass and lower moveable eyeglass have vertical adjustment function, upper movable eyeglass is used for compensating mask partial face shape high-order amount, and lower moveable eyeglass is used for compensating substrate partial face shape high-order amount；Mask focusing and leveling system and substrate focusing and leveling system are between two row object lens, and mask focusing and leveling system is positioned at the surface of substrate focusing and leveling system.

Further, the movement locus of upper movable eyeglass, lower moveable eyeglass and work stage is Legendre multinomial or other orthogonal polynomial track.

Present invention simultaneously discloses a kind of method measuring and correct material fluctuating, comprise the steps: that the vertical sensor of step one, mask platform controls mask platform height and tilts constant, use mask focusing and leveling sensor to measure mask plane shape；It is constant that the vertical sensor of step 2, work stage controls Workpiece stage vertical position, uses substrate focusing and leveling sensor to measure real estate shape；Step 3, based on mask plane shape compensation model, mask plane shape is split as low order amount and high-order amount part, is compensated work stage adjustment amount and the top object lens adjustment amount of mask plane shape；Step 4, based on real estate shape compensation model, real estate shape is split as low order amount and high-order amount part, is compensated work stage adjustment amount and the lower section object lens adjustment amount of real estate shape；Step 5, to compensate mask plane shape work stage adjustment amount and compensate real estate shape work stage adjustment amount merge, be fitted obtaining work stage movement locus；According to top object lens adjustment amount and lower section object lens adjustment amount, it is fitted obtaining upper movable eyeglass and the movement locus of lower moveable eyeglass；Object lens, lower section object lens and work stage hybrid compensation mask and real estate shape above step 6, adjustment.

Further, fit to use Legendre fitting of a polynomial, or other way of fitting described in.

Compared with prior art, the present invention uses work stage and the mode of object lens movable lens Joint regulation, carries out mask gravity deformation and real estate shape splitting compensation.During scan exposure, by adjusting camera lens top half movable agency in real time, compensate mask plane shape high-order amount；By adjusting camera lens the latter half movable agency in real time, compensate real estate shape high-order amount；By adjusting work stage in real time, compensate the low order amount in mask plane shape and real estate shape.By using 6 small field of view object lens splicing compositions to make light field public, reduce time of exposure with this, reduce manufacture difficulty and cost.The present invention improves the system performance index such as TFT photo-etching machine exposal resolution and productivity.

Accompanying drawing explanation

Can be described in detail by invention below about the advantages and spirit of the present invention and institute's accompanying drawings is further understood.

Fig. 1 is the structural representation of the lithographic equipment that recoverable material provided by the present invention rises and falls；

Fig. 2 is that movable lens adjusts one of principle schematic；

Fig. 3 is that movable lens adjusts the two of principle schematic；

Fig. 4 is mask platform vertical position schematic diagram；

Fig. 5 is facula measurement value schematic diagram；

Fig. 6 is plane fitting schematic diagram；

Fig. 7 is the flow chart of the photoetching method that recoverable material provided by the present invention rises and falls.

Detailed description of the invention

Describe the specific embodiment of the present invention below in conjunction with the accompanying drawings in detail.

For defect present in prior art, in order to compensate two kinds of face shapes adverse effect to exposure effect respectively, the technical program devises a set of lithographic equipment, by adjusting work stage and object lens upper and lower two parts movable lens in real time, correction mask version gravity deformation and real estate shape, make exposure field upper surface in exposure process overlap with exposure focal plane.

In the present invention, use work stage and the mode of object lens movable lens Joint regulation, carry out mask gravity deformation and real estate shape splitting compensation.During scan exposure, by adjusting camera lens top half movable agency in real time, compensate mask plane shape high-order amount；By adjusting camera lens the latter half movable agency in real time, compensate real estate shape high-order amount；By adjusting work stage in real time, compensate the low order amount in mask plane shape and real estate shape.

For current large-sized substrate, in order to ensure productivity, the technical program uses splicing camera lens method, by one big visual field of rectangle of 6 small field of view object lens splicing compositions.

Below with reference to accompanying drawing 1-7, describe lithographic equipment and the implementation of method that recoverable material provided by the present invention rises and falls in detail.

Fig. 1 schematically illustrates the lithographic equipment of according to one embodiment of present invention 1.According to embodiments of the invention, it is provided that a kind of lithographic equipment, comprising: illuminator 1, mask 2, mask platform 3, the vertical sensor of mask platform 4, mask focusing and leveling system 5, substrate focusing and leveling system 6, objective lens array 7, substrate 8, work stage 9, the vertical sensor of work stage, executor 10.In addition, this lithographic equipment also includes: mask focusing and leveling systematic survey hot spot 11, substrate focusing and leveling systematic survey hot spot 12.

Each subsystem function and mutual relation be: during off-line Mapping (measurement of face row), mask focusing and leveling system 5 and substrate focusing and leveling system 6 measure mask 2 lower surface and substrate 8 upper surface face shape respectively.During scan exposure, illuminator 1 launches illuminating bundle, it is irradiated on mask 2, it is imaged onto on real estate 8 through objective lens array 7, the vertical sensor of mask platform 4 controls mask platform 3 catenary motion, mask focusing and leveling system 5 measures mask plane shape, and the vertical sensor of work stage 10 controls work stage 9 and carries substrate 8 catenary motion, and substrate focusing and leveling system 6 carries out substrate surface shape measurement.

Compared with prior art, the objective lens array 7 of the present invention is made up of multiple camera lenses, and its visual field is made up of multiple camera lenses, and camera lens uses catadioptric principle.Each of which camera lens all includes upper part movable lens and lower part movable lens, and two parts are Independent adjustable complete machine structure.Splicing view field is by two row object lens (objective lens array 7), and totally 6 Ge Dan objective angular fields form.Mask focusing and leveling system 5 and substrate focusing and leveling system 6 are between two row object lens 7, and substrate focusing and leveling system 6 is positioned at immediately below mask focusing and leveling system 5.

The present invention passes through upper part movable lens and lower part movable lens, mask plane shape is split as low order amount and high-order amount, work stage adjustment amount compensates mask plane shape low order amount, each object lens upper part movable lens compensates mask partial face shape high-order amount, work stage and object lens upper part movable lens combine regulation and compensates mask plane shape.Real estate shape is split as low order amount and high-order amount, and work stage adjustment amount compensates real estate shape low order amount, and each object lens lower part movable lens compensates substrate partial face shape high-order amount, work stage and object lens lower part movable lens combine regulation and compensates real estate shape.

Movable lens is adjusted and can be realized by the following two kinds mode:

Mode one: vertical adjustment lens 21, it is achieved vertical adjustment object lens focal plane 22, as shown in Figure 2.

Mode two: level is to adjusting movable lens group eyeglass 21, it is achieved vertical adjustment object lens focal plane 22, as shown in Figure 3.

Fig. 4 is mask platform vertical position schematic diagram.As shown in Figure 4, mask platform 3 height measured by the vertical sensor of mask platform 4, and mask focusing and leveling 5 measures mask plane shape 2 and mask datum plate labelling height.

The present invention also provides for a kind of method measuring material fluctuating, comprises the following steps:

The vertical sensor of the first step, mask platform controls mask platform vertical position, uses mask focusing and leveling systematic survey mask plane shape；

The vertical sensor of second step, work stage controls Workpiece stage vertical position, uses substrate focusing and leveling systematic survey real estate shape；

3rd step, based on mask plane shape compensation model, mask plane shape is split as work stage adjustment amount and object lens upper part adjustment amount；

4th step, based on real estate shape compensation model, real estate shape is split as work stage adjustment amount and object lens lower part adjustment amount；

5th step, to each several part adjustment amount use Legendre fitting of a polynomial, calculate Legendre multinomial coefficient (C0, C1, C2, C3, C4), it is handed down to work stage and object lens top and the bottom movable lens, controls work stage and object lens top and the bottom movable lens movement locus during scan exposure.

Based on mask plane shape compensation model, mask plane shape is split as work stage adjustment amount and object lens upper part adjustment amount is specific as follows:

As shown in Figure 4, mask platform height measured by the vertical sensor of mask platform 4, and mask focusing and leveling system 5 measures mask plane shape and mask datum plate labelling height.

Mask plane shape compensation model, calculates work stage adjustment amount

Mask plane shape is relative mask platform datum plate face shape, shown in computing formula such as formula (1):

Δz_reticle(x_i,y_i)=((z_{FLS_spot}-z_ENC(x_i,y_i))-(Z_plate+Rx_plate*y_i-Ry_plate*x_i) ………(1)

Above formula respectively measures physical meaning:

1) (x, y) for the reading of the vertical sensor of mask platform during measurement mask plane shape for zENC；

2) Zplate, Rxplate, Ryplate, the height of datum plate and tilting value；

3) zFLS_spot is the measurement height value of the mask each hot spot of focusing and leveling system；

4)Δz_reticlePoor relative to the face shape of mask platform datum plate for mask plane shape；

5) xi, yi are each measurement point horizontal level on mask.

After mask plane shape is corresponded to image planes, corresponding x, y, z expression formula is:

$\left\{\begin{array}{c}\mathrm{\Δz}(x,y)=\mathrm{\Δ}{z}_{\mathrm{reticle}}(x,y)*M^2\\ x=x_{\mathrm{ws}}+x_{\mathrm{reticle}\_i}*M\\ y=y_{\mathrm{ws}}+y_{\mathrm{reticle}\_i}*M\end{array}\right....\left(2\right)$

Above formula respectively measures physical meaning:

1) x, y are the measurement point position after being transformed into image planes；

2)x_ws, y_wsFor exposure field center；

3)Δ_zFor mask plane shape relative to the difference of mask platform datum plate；

4)x_{reticle_i}, y_{reticle_i}Point horizontal level is measured for mask coordinates system；

5) M is lens ratio.

Use static visual field moving average, calculate x to along the matching face setting value at a series of y location of exposure center.

Each matching face setting value Z (y), Rx (y), Ry (y), utilize all point Linear matchings in current Slit (static visual field) to obtain:

z_i=ax_i+by_i+c ……………………(3)

Wherein, xi, yi, zi represent mask mapping measure point forward image planes to after, at each y location in Slit all of mask mapping measure point.

As shown in Figure 6, in Slit sliding process, measure point with mask mapping in Slit and (after forwarding image planes to, see that formula (2) does plane fitting, obtain matching face setting value Z (y), Rx (y), Ry (y).

Matching face height and tilt expression formula be:

$\left\{\begin{array}{c}z\_s_{\mathrm{reticle}}\left(y\right)=a*x_{\mathrm{center}}+b*y+c\\ \mathrm{Rx}\_s_{\mathrm{reticle}}\left(y\right)=b\\ \mathrm{Ry}\_s_{\mathrm{reticle}}\left(y\right)=-a\end{array}\right....\left(4\right)$

In above formula, each amount physical meaning is as follows:

Z_sreticle (y), Rx_sreticle (y), Ry_sreticle (y): for compensating only for mask plane shape, each y location correspondence static state visual field vertical setting value of work stage；

Y is that y belongs to [y to the position of scanning along y_start,y_end],y_startIt is to start exposure position, y_endIt is to terminate exposure position.

Calculate object lens upper part adjustment amount to specifically include:

All some meansigma methodss of measuring under the single object lens of calculating: ${\stackrel{\‾}{z}}_i=\frac{\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{z}_{\mathrm{ij}}}{n}...\left(5\right)$

Above formula each physical quantity implication is as follows:

1) zij all mask mapping measured values under being i-th camera lens；

2)For the meansigma methods of the z of j point under i-th camera lens.

Single-lens adjustment amount: ${\mathrm{dz}}_i\left(y\right)={\stackrel{\‾}{z}}_i-z\_s_i\left(y\right)...\left(6\right)$

Above formula each physical quantity implication is as follows:

1) dzi is the adjustment amount of single camera lens；

2) z_si (y) is the height value in whole static matching face, visual field of i-th optical center.

z_s_i(y)=a*x_i+b*y_i+c ……………………(7)

Above formula each physical quantity implication is as follows:

1) a, b, c are six facula measurement values of mask focusing and leveling 5 floor coefficients of matching at different y location；

2) xi, yi are position, each optical center.

Real estate shape compensation model, calculates work stage adjustment amount specific as follows:

As it is shown in figure 5, each hot spot original measurement value is transformed into the height under optical axis it is:

z_{spot_FLS}(x, y)=z_{spot_raw}+Ry_BF*x_spot-Rx_BF*y_spot ……………………(8)

It is as follows that above formula respectively measures physical meaning:

1)x_spot、y_spotHorizontal level for hot spot；

2)z_{spot_raw}Original measurement value for each hot spot；

3)z_{spot_FLS}Height value after changing for each hot spot；

4)Rx_BF、Ry_BFTilting value for optimum exposure focal plane.

The vertical measurement value sensor of work stage that each facula measurement point is corresponding is:

z_s_{spot_IFM}(x, y)=z_s-Ry_s*x_spot+Rx_s*y_spot……………………(9)

It is as follows that above formula respectively measures physical meaning:

1)x_spot、y_spotHorizontal level for hot spot；

2) z_s, Rx_s, Ry_s are height and the inclination of current work stage, and its value is equal to the measured value of the vertical sensor of work stage；

3)z_s_{spot_IFM}The vertical measurement value sensor of work stage corresponding during for each facula measurement position under optical axis.

Real estate shape expression formula is:

z_{wafer_map}(x, y)=z_s_{spot_IFM}(x,y)+Z_BF-z_{spot_FLS}(x,y) ……………………(10)

It is as follows that above formula respectively measures physical meaning:

1)z_{spot_FLS}Height value after changing for each hot spot；

2)z_s_{spot_IFM}The vertical measurement value sensor of work stage corresponding during for each facula measurement position under optical axis；

3)Z_{_BF}Height value for optimum exposure focal plane；

4)z_{wafer_map}For original real estate shape.

Use static visual field moving average, calculate x to along the matching face setting value at a series of y location of exposure center.

Each matching face setting value Z (y), Rx (y), Ry (y), utilize all point Linear matchings in current Slit (static visual field) to obtain:

z_i=ax_i+by_i+c ……………………(11)

Wherein, x_i,y_i,z_iRepresent at each y location all of real estate shape mapping in Slit and measure point.

As shown in Figure 6, in Slit sliding process, measure point by real estate shape mapping in Slit and do plane fitting, obtain matching face setting value Z (y), Rx (y), Ry (y).

Matching face height and tilt expression formula be:

$\left\{\begin{array}{c}z\_s_{\mathrm{plate}}\left(y\right)=a*x_{\mathrm{center}}+b*y+c\\ \mathrm{Rx}\_s_{\mathrm{plate}}\left(y\right)=b\\ \mathrm{Ry}\_s_{\mathrm{plate}}\left(y\right)=-a\end{array}\right....\left(12\right)$

In above formula, each amount physical meaning is as follows:

z_s_plate(y)、Rx_s_plate(y)、Ry_s_plate(y): for compensating only for real estate shape, each y location correspondence static state visual field vertical setting value of work stage；

Y is that y belongs to [y to the position of scanning along y_start,y_end],y_startIt is to start exposure position, y_endIt is to terminate exposure position.Calculate object lens lower part adjustment amount

All some meansigma methodss of measuring under the single object lens of calculating: ${\stackrel{\‾}{z}}_i=\frac{\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{z}_{\mathrm{ij}}}{n}...\left(13\right)$

Above formula each physical quantity implication is as follows:

1)z_ijFor substrate mapping measured values all under i-th camera lens；

2)For the meansigma methods of the z of j point under i-th camera lens.

Single-lens adjustment amount: ${\mathrm{dz}}_i\left(y\right)={\stackrel{\‾}{z}}_i-z\_s_i\left(y\right)...\left(14\right)$

Above formula each physical quantity implication is as follows:

1)dz_iAdjustment amount for single camera lens；

2)z_s_iY () is the height value in whole static matching face, visual field of i-th optical center.

z_s_i(y)=a*x_i+b*y_i+c ……………………(15)

Above formula each physical quantity implication is as follows:

1) a, b, c are six facula measurement values of substrate focusing and leveling system 6 floor coefficients of matching at different y location；

2)x_i, y_iFor position, each optical center.

Legendre fitting of a polynomial

Work stage adjustment amount fitting of a polynomial

Compensate mask plane shape, work stage adjustment amount z_s_reticle(y)、Rx_s_reticle(y)、Ry_s_reticle(y)；

Compensate real estate shape, work stage adjustment amount z_s_plate(y)、Rx_s_plate(y)、Ry_s_plate(y)；

To when compensating mask plane shape, work stage adjustment amount does Legendre fitting of a polynomial, can obtain formula (16) Legendre multinomial:

$f_{\mathrm{reticle}}\left(x\right)=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}{k}_i{L}_i\left(x\right),m\≤5,x\∈[-\mathrm{1,1}]...\left(16\right)$

To when compensating real estate shape, work stage adjustment amount does Legendre fitting of a polynomial, can obtain formula (17) Legendre multinomial:

$f_{\mathrm{plate}}\left(x\right)=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}{k^{\′}}_i{L}_i\left(x\right),m\≤5,x\∈[-\mathrm{1,1}]...\left(17\right)$

Final work stage adjustment amount Legendre multinomial is shown in formula (18):

$g\left(x\right)=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}(k_i+{k^{\′}}_i)L_i\left(x\right),m\≤5,x\∈[-\mathrm{1,1}]...\left(18\right)$

Single object lens adjustment amount fitting of a polynomial

Single object lens adjustment amount dz_i(y), corresponding Legendre multinomial is as follows:

$h\left(x\right)=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}{k^{\′\′}}_i{L}_i\left(x\right),m\≤5,x\∈[-\mathrm{1,1}]...\left(19\right)$

Fig. 7 is the flow chart of the photoetching method that recoverable material provided by the present invention rises and falls.Wherein 701 to 714 is based on real estate shape compensation model, and real estate shape is split as work stage adjustment amount and the idiographic flow of object lens lower part adjustment amount.801 to 814 is based on mask plane shape compensation model, and mask plane shape is split as work stage adjustment amount and object lens upper part adjustment amount.Each several part adjustment amount is used Legendre fitting of a polynomial, calculates Legendre multinomial coefficient (C0, C1, C2, C3, C4), it is handed down to work stage and object lens top and the bottom movable lens, controls work stage and object lens top and the bottom movable lens movement locus during scan exposure.The calculation of concrete each adjustment amount is as described above.

The preferred embodiment of the simply present invention described in this specification, above example is only in order to illustrate technical scheme rather than limitation of the present invention.All those skilled in the art, all should be within the scope of the present invention under this invention's idea by the available technical scheme of logical analysis, reasoning, or a limited experiment.

Claims (4)

1. the lithographic equipment that a recoverable material rises and falls, it is characterised in that including:

Illuminator, for providing a lithographic beam；

Mask platform, is used for carrying mask；

The vertical sensor of mask platform, for detecting and control the vertical position of a mask platform；

Mask focusing and leveling system, for measuring the face shape of mask；

Work stage, moves for bearing substrate, compensates mask and the low order amount of real estate shape；

Substrate focusing and leveling system, for measuring the face shape of substrate；

The vertical sensor of work stage, for detecting and control the vertical position of a work stage；

Objective lens array, the two row object lens being made up of multiple single object lens, single object lens include upper movable eyeglass and lower moveable eyeglass, described upper movable eyeglass and lower moveable eyeglass have vertical adjustment function, upper movable eyeglass is used for compensating mask partial face shape high-order amount, and lower moveable eyeglass is used for compensating substrate partial face shape high-order amount；

Mask focusing and leveling system and substrate focusing and leveling system are between two row object lens, and mask focusing and leveling system is positioned at the surface of substrate focusing and leveling system.

2. the lithographic equipment that recoverable material as claimed in claim 1 rises and falls, it is characterised in that the movement locus of upper movable eyeglass, lower moveable eyeglass and work stage is Legendre multinomial or other orthogonal polynomial track.

3. measure and correct the method that material rises and falls, comprise the steps:

The vertical sensor of step one, mask platform controls mask platform height and tilts constant, uses mask focusing and leveling sensor to measure mask plane shape；

It is constant that the vertical sensor of step 2, work stage controls Workpiece stage vertical position, uses substrate focusing and leveling sensor to measure real estate shape；

Step 3, based on mask plane shape compensation model, mask plane shape is split as low order amount and high-order amount part, is compensated work stage adjustment amount and the top object lens adjustment amount of mask plane shape；

Step 4, based on real estate shape compensation model, real estate shape is split as low order amount and high-order amount part, is compensated work stage adjustment amount and the lower section object lens adjustment amount of real estate shape；

Step 5, to compensate mask plane shape work stage adjustment amount and compensate real estate shape work stage adjustment amount merge, be fitted obtaining work stage movement locus；According to top object lens adjustment amount and lower section object lens adjustment amount, it is fitted obtaining upper movable eyeglass and the movement locus of lower moveable eyeglass；

Object lens, lower section object lens and work stage hybrid compensation mask and real estate shape above step 6, adjustment.

Measure and correct the method that material rises and falls the most as claimed in claim 3, it is characterised in that described in fit to use Legendre fitting of a polynomial, or other way of fitting.